Bulgaria issued in 2017 one stamp for the 100th years Bulgarian Naval Aviation, which shows us a helicopter with on the right a naval vessel.
By looking at the Bulgarian navy ships photos not one ship did look the same as on the stamp.

I found that the Bulgarian Government did have plans to buy or build a new type of corvette based on the plans of the French Gowind class corvette https://en.wikipedia.org/wiki/Gowind-class_corvette . Comparing this with the ship on the stamp, the hull is the same only she has two masts which is not visible on the photo.

Bulgaria 2017 0.65L. sg?, scott?